Corrosion, Stress Corrosion Cracking, andnElectrochemistry of the Iron and Nickel BasenAlloys in Caustic Environments Progress Report for the Period 1 March 1978 to 28 February 1979

摘要

Stress corrosion cracking susceptibility of 2-l/4Cr-lMo steel has been studied in the pH range 0.5 to 13 in one molar sulfate solutions containing Na2S additions, by the slow strain rate (10-6 S-1 ) technique. Brittle fracture was observed over the entire pH range but only at cathodic potentials which were below the hydrogen evolution region. Fractures at cathodic potentials were probably due to the hydrogen embrittlement which was accentuated by the sulfide present in the environment. At anodic potentials failures in straining tests were due to either general corrosion or mechanical ductile fracture.nCrack propagation rates (CPRs) in Nickel-200 have been measured as a function of potential in 17.5N NaOH solution at 138°C, using the fast straining electrode technique.